emailler/client/ip65/parser.s

84 lines
1.6 KiB
ArmAsm

;text file parsing routines
; first call parser_init
; then call parser_skip_next
.export parser_init
.export parser_skip_next
.importzp copy_src
.importzp copy_dest
target_string=copy_src
search_string=copy_dest
.include "../inc/common.i"
.ifndef NB65_API_VERSION_NUMBER
.define EQU =
.include "../inc/nb65_constants.i"
.endif
.bss
temp_ptr: .res 2
.segment "SELF_MODIFIED_CODE"
get_next_byte:
current_string_ptr=get_next_byte+1
lda $ffff
inc current_string_ptr
bne :+
inc current_string_ptr+1
:
pha
pla ;reload A so flags are set correctly
rts
.code
;set up a string for parsing
;inputs: AX = pointer to (null terminated) string to be parsed
;outputs: none
parser_init:
stax current_string_ptr
clc
rts
;advance pointer along till just past the next occurance of specified string
;inputs: AX= pointer to (null terminated) string to search for
;outputs: sec if search string not found
; if clc, AX = pointer to first byte after string specified
; if sec (i.e. no match found), pointer stays in same place
parser_skip_next:
stax search_string
ldax current_string_ptr
stax temp_ptr
@check_string:
ldy #0
ldax current_string_ptr
stax target_string
@check_next_char:
lda (search_string),y
beq @matched
cmp (target_string),y
bne @not_matched
iny
bne @check_next_char
@matched:
;now skip 'y' bytes
@skip_byte:
jsr get_next_byte
dey
bne @skip_byte
ldax current_string_ptr
clc
rts
@not_matched:
jsr get_next_byte
bne @check_string
ldax temp_ptr
stax current_string_ptr
sec
rts